With reference to 'fuel cells' in which hydrogen-rich fuel and oxygen are used to generate electricity, consider the following statements : 1. If pure hydrogen is used as a fuel, the fuel cell emits heat and water as by-products. 2. Fuel cells can be used for powering buildings and not for small devices like laptop computers. 3. Fuel cells produce electricity in the form of Alternating Current (AC). Which of the statements given above is/are correct?
- (a) 1 only ✓ UPSC's answer
- (b) 2 and 3 only
- (c) 1 and 3 only
- (d) 1, 2 and 3
Why the answer is (a)
• A hydrogen fuel cell combines hydrogen and oxygen electrochemically; with pure hydrogen the only by-products are water and heat (statement 1).
• Statement 2 is wrong: fuel cells power everything from buildings and vehicles to portable devices such as laptops and phones (micro fuel cells).
• Statement 3 is wrong: fuel cells produce direct current, which is converted to AC by an inverter where needed.
• Hence 1 only, option (a).
Why the other options are wrong
- (b) 2 and 3 only
- Statements 2 and 3 are wrong: fuel cells power small devices and produce DC.
- (c) 1 and 3 only
- Statement 3 is wrong: fuel cells produce DC.
- (d) 1, 2 and 3
- Statements 2 and 3 are wrong.
Asked in the GS Paper I of the UPSC Civil Services Preliminary Examination 2015, held on 23 August 2015. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.